Background technology
Lithium ion battery is gradually by the electronic product extensive use, as mobile phone, and notebook computer, electric tool etc.Be accompanied by the lightening trend of consumption electronic product, it is more and more important that flexible packing lithium ion battery becomes, and its production capacity and output also are doubled and redoubled, and the trend that replaces gradually traditional 18650 type lithium batteries is arranged greatly in fields such as notebook computers.But use security risk still to exist, as when overcharging, the oxidation under inside battery generation negative electrode high voltage and anode analyse the lithium reaction, cause that temperature rises rapidly, because heat can not in time conduct, can cause the battery Ignition Phenomena.
For preventing that at present flexible packing lithium ion battery non-ignitable technical scheme when overcharging from having: TCO(Thermal Cutoffs is used in the lug junction outside packing; Thermal Cutoffs) or PTC(Positive Temperature Coefficient; positive temperature coefficient) thermistor or equitemperature sensitive electrical devices; when because of voltage or the too high heat production of electric current; resistance raises rapidly, thereby and then reduces or cut off electric current to reach the protection purpose.But there are two problems in this technical scheme: one, cost improves greatly.Most high-quality TCO are all the companies such as Japanese firm such as Xiao Song and make, and are in monopoly position, and price is higher, need simultaneously to be contracted out to the PACK(encapsulation) the installation TCO of company, further increased processing cost.Two, the response temperature of TCO is difficult to and the battery coupling, if the TCO response temperature is too high, and the response that also is not able to do in time when overcharging, battery catches fire; If response temperature is too low, when battery carries out high-multiplying power discharge, because making the TCO response, the heat production meeting can't complete required high-multiplying power discharge.
When overcharging, battery has the characteristic of an aerogenesis dilatancy not to be used in the technical scheme of above temperature-sensitive element.Yet adopt in Chinese patent application CN200910160087.8 and paste the hardboard sheet outside packing.When battery outwards expanded, plate drove a mechanical device and disconnects utmost point handle and reach the outage purpose.Although this scheme has been utilized the cell expansion characteristic, the add-in card sector-meeting increases the cell thickness decrease of power density, and the mechanical device of the outer lug of packing top closing takies the length space equally, and is difficult to guarantee each accurately response.Adopted the built-in electronic protection circuit in Chinese patent application CN201120179905.1.This scheme not only can cause owing to taking up room energy content of battery density to reduce, and also can increase because electronic devices such as adopting relay causes the battery cost.
The utility model content
In view of the problem in background technology, the purpose of this utility model is to provide a kind of flexible packing lithium ion battery and lug thereof, wherein lug can be heated and destroy when stressed because expanding at flexible packing lithium ion battery, thereby improves the security performance of flexible packing lithium ion battery.
Another purpose of the present utility model is to provide a kind of flexible packing lithium ion battery and lug thereof, and it does not affect the energy density of flexible packing lithium ion battery.
Another purpose of the present utility model is to provide a kind of flexible packing lithium ion battery and lug thereof, and its high power discharge operation that can guarantee flexible packing lithium ion battery is carried out smoothly.
To achieve these goals, in first aspect, the utility model provides a kind of lug of flexible packing lithium ion battery, and it comprises: encapsulation will be encapsulated in the top closing place of the package foil of flexible packing lithium ion battery; Connecting portion will be connected with the pole piece of flexible packing lithium ion battery; And disconnecting unit, be arranged in the scope of encapsulation and connecting portion, to be heated at flexible packing lithium ion battery and to disconnect when stressed because expanding.
To achieve these goals, in second aspect, the utility model provides a kind of flexible packing lithium ion battery, and it comprises: anode pole piece; Cathode pole piece; Barrier film is arranged between anode pole piece and cathode pole piece; Positive pole ear is electrically connected on anode pole piece; Negative lug is electrically connected on cathode pole piece; And package foil, with anode pole piece, cathode pole piece and barrier film encapsulation in the inner; Wherein, positive pole ear and/or negative lug adopt the lug according to the described flexible packing lithium ion battery of the utility model first aspect.
The beneficial effects of the utility model are as follows:
Disconnecting unit is because being heated and because of stressed fracture of expanding, thereby battery core is cut off the power supply rapidly, thus the fail safe that has improved flexible packing lithium ion battery.
Based on the design of lug, the lug size does not increase, thereby does not affect the energy density of flexible packing lithium ion battery, and can guarantee that the high power discharge performance of flexible packing lithium ion battery carries out smoothly, makes simply, has reduced production cost.
Description of drawings
Fig. 1 is the structural representation according to flexible packing lithium ion battery of the present utility model, wherein for for the purpose of removing, only illustrates with a lug;
Fig. 2 to Fig. 6 be according to the lug of the flexible packing lithium ion battery of different embodiment of the present utility model structural representation;
Fig. 7 is the structural representation according to flexible packing lithium ion battery of the present utility model;
Fig. 8 arranges the structural representation of relation according to the pole piece of flexible packing lithium ion battery of the present utility model and barrier film;
Fig. 9 is according to the structural representation of flexible packing lithium ion battery of the present utility model before overcharging;
Figure 10 is according to the structural representation of flexible packing lithium ion battery of the present utility model after overcharging.
Wherein, description of reference numerals is as follows:
1 pole piece 322 stage portion
1A anode pole piece H2 height
1B cathode pole piece 33 disconnecting units
2 barrier film 3A positive pole ears
3 lug 3B negative lug
The 31 first lug T of section thickness
311 encapsulation 4 package foil
312 stage portion 41 top closings
H1 height 5 battery cores
32 second lug section 6 rivets
321 connecting portions
Embodiment
Describe in detail with reference to the accompanying drawings according to flexible packing lithium ion battery of the present utility model and lug thereof.In Fig. 1 to Fig. 7, for convenience of explanation, adopt dotted line or dotted line frame to indicate the position of encapsulation, weld part, disconnecting unit.
At first lug according to the flexible packing lithium ion battery of the utility model first aspect is described.
To shown in Figure 6, have according to the lug 3 of flexible packing lithium ion battery of the present utility model: encapsulation 311 will be encapsulated in top closing 41 places of the package foil 4 of flexible packing lithium ion battery as Fig. 1; Connecting portion 321 will be connected with the pole piece 1 of flexible packing lithium ion battery; And disconnecting unit 33, be arranged in the scope of encapsulation 311 and connecting portion 321, to be heated at flexible packing lithium ion battery and to disconnect when stressed because expanding.
For the setting position of disconnecting unit 33, disconnecting unit 33 can be arranged on connecting portion 321 places or be arranged on encapsulation 311 and connecting portion 321 between.
In an embodiment of lug 3, as shown in Figure 2, Figure 3, Figure 4, lug 3 can comprise: the first lug section 31 has encapsulation 311; And the second lug section 32, have connecting portion 321 and be connected with the first lug section 31; Wherein, disconnecting unit 33 part that to be the first lug section 31 be connected with the second lug section 32.In embodiment as shown in Figure 2, Figure 3, Figure 4, lug 3 is the two-part structure.Adopt the lug 3 of two-part structure, when lug 3 because of expand stressed and when being heated disconnecting unit 33 can disconnect, to reach the function of outage.
In the lug 3 that adopts the two-part structure, preferably, as shown in Figure 2, Figure 3, Figure 4, the first lug section 31 is provided with stage portion 312, the stage portion 322 that the second lug section 32 is provided with the stage portion 312 of stage portion 322, the first lug sections 31 and the second lug section 32 is complementary and cooperatively interact on how much.Preferably, the height H 2 of the stage portion 322 of the height H 1 of the stage portion 312 of the first lug section 31 and the second lug section 32 is less than half of the thickness T of lug 3, according to the sectional area larger principle of small resistor more, when the flexible packing lithium ion battery that adopts this lug overcharges, in the programming rate at disconnecting unit 33 places all the other positions greater than lug 3, preferentially reach alloy or PUR fusion temperature, thereby effectively disconnect.Height H 1 and height H 2 are preferably 0.02~0.5mm.
In the lug 3 that adopts the two-part structure, the first lug section 31 and the second lug section 32 can by fusing point be 70~90 ℃ the alloy welding (for Fig. 2 be connected structure), softening temperature be the glue of 70~90 ℃ or adhesive tape bonding (for Fig. 2 be connected structure), fusing point be 70~90 ℃ resistance welded (for Fig. 2 be connected structure), fusing point be the alloy of 70~90 ℃ rivet (as Fig. 4 by rivet 6) or laser welding (for Fig. 2 be connected structure) be connected.
In another embodiment of lug 3, as shown in Figure 4 and Figure 5, lug 3 in the scope of encapsulation 311 and connecting portion 321 take interior as monolithic structure, and disconnecting unit 33 dotted line (as Fig. 6) or the imaginary point (as Fig. 5) that go out for machining.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, lug 3 can be made by one or more different metals or alloy.Preferably, lug 3 is become by nickel or copper.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, the seamed edge place of lug 3 is chamfering.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, the width of lug 3 is that 1~10mm, thickness T are 1~1000 μ m.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, the width of lug 3 is that 3~6mm, thickness T are 50~200 μ m.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, the distance between disconnecting unit 33 and encapsulation 311 is 1~30mm, preferred 2~12mm, wherein, this distance with both separately the lug length between central point calculate.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, the distance between encapsulation 311 and connecting portion 321 is 1~10mm, be preferably 2~6mm, this distance with both separately the lug length between central point calculate.
In the lug 3 according to flexible packing lithium ion battery described in the utility model, pole piece 1 can be anode pole piece 1A and lug 3 for positive pole ear 3A or pole piece 1 can be cathode pole piece 1B lug 3 for negative lug 3B(simultaneously with reference to Fig. 7 and Fig. 8).
The following describes flexible packing lithium ion battery described according to the utility model second aspect.
As shown in Figure 7 and Figure 8, comprise according to flexible packing lithium ion battery of the present utility model: anode pole piece 1A; Cathode pole piece 1B; Barrier film 2 is arranged between anode pole piece 1A and cathode pole piece 1B; Positive pole ear 3A is electrically connected on anode pole piece 1A; Negative lug 3B is electrically connected on cathode pole piece 1B; And package foil 4, anode pole piece 1A, cathode pole piece 1B and barrier film 2 are encapsulated in the inner; Wherein positive pole ear 3A and/or negative lug 3B adopt the lug 3 according to the described flexible packing lithium ion battery of the utility model first aspect.
At last to overcharge as the work of example explanation flexible packing lithium ion battery and lug thereof.
Fig. 9 and Figure 10 illustrate flexible packing lithium ion battery described in the utility model and the change procedure of lug when overcharging thereof.
as shown in Figure 9 and Figure 10, when flexible packing lithium ion battery when overcharging, along with voltage raises, can produce rapidly gas and cause the outside dilatancy of battery core 5, this gross distortion that produces that expands can pull the lug (only representing with positive pole ear 3A in the drawings) that is connected on pole piece simultaneously, and the other end of lug is fixed on the top closing place, thereby produce one to the tension force that pulls of lug, (namely whole is a slice but this pulls tension force also to be not enough to break common lug, be not provided with disconnecting unit of the present utility model), meanwhile, heating up (being heated) under the high voltage of lug when overcharging and the fusing even melt, thereby break lug (being that disconnecting unit 33 disconnects) by means of overcharging under the acting in conjunction that causes pulling force that dilatancy produces and intensification melting, reach timely cut-out electric current.
With respect to prior art, the flatulence when the utility model can take full advantage of battery core and overcharges when overcharging and the dual character of intensifications have been evaded the side effect of conventional art or patent generation.Be based on the life size of lug, additionally do not increase thickness to avoid the decrease of power density.While without expansion, can not produce the pulling force effect to the utility model lug because of battery core in the intensification situation that causes because of large electric current merely, therefore also can not cause the place's resistance rising of the utility model lug or open circuit.Can adopt low-temperature alloy material at a low price or adhesive material or simple and mechanical processing at a low price on cost of manufacture, thereby greatly reduce production cost.
Except not increasing the lug size, adopt low-temperature alloy material or hot melt conductive adhesive material or simple and mechanical processing at a low price on making, solved well the abnormal problem that traditional insurance silk structure disconnects in the temperature rise that causes because of high power discharge merely, simultaneously in battery core high power discharge process because produce without the effect of expansion pulling force, therefore can not cause the utility model battery core resistance raise or open circuit, have practical application widely.
Certain flexible packing lithium ion battery of the present utility model and lug thereof are not limited to overcharge, the high power discharge situation, go for any based on variations in temperature and the battery core situation that required lithium ion battery opens circuit that expands.